Modem armament systems for military applications are increasingly complex. Typically, there are a plurality of disparate components that are controlled by a complex control system, which coordinates and integrates the operation of each component in the system.
In the early stages of evolution, armament control systems were merely a series of mechanical mechanisms that allowed an operator to activate a particular component using the judgment of the operator. One such example is the mechanical linkage for weapons release on early military aircraft. When the pilot determined the plane was at the correct location, the pilot would actuate a particular linkage from the cockpit, thereby releasing the related weapon. With the advent of electronic control systems, the remote release of a particular weapon component controlled by such a system became possible. An electronic switch in the cockpit of the military aircraft would send a signal through dedicated wiring to a weapon actuator, thereby releasing a particular weapon.
The next stage in the evolution of armament systems was the integration of computer control into the armament system. Targeting control computers were combined with data acquired from sources such as radar systems to aide the operator in target acquisition, thereby improving on-target percentages. U.S. Pat. No. 4,004,729 is an example of such a system that provides an automated fire control apparatus. The control system of this patent connects a radar tracking system with a targeting computer and weapon positioning means. The computer control system provides a larger period of time during which the weapon may be successfully fired at the intended target.
As computer systems became more powerful, it became more common to centralize the control functions in a single armament control system that could manage multiple diverse armament components. U.S. Pat. No. 5,229,538 is an example of one type of centralized armament control system. This patent provides a digital communications armament system for controlling a carriage of “smart” weapons. The smart weapons are carried by the aircraft in a Multiple Carriage Rack (MCR). The weapons in the MCR are programmed and controllably released as part of a weapons control system. The components of this system are communicably interconnected by a single databus as described in MIL-STD-1553. The military standard 1553 bus is a dual redundant bus comprising two shielded twisted pair cables, a bus controller, and a plurality of remote terminals.
U.S. Pat. No. 5,036,466 is another example of a centralized armament control system. This provides a central control unit that also is communicably connected by a MIL-STD-1553 bus to multiple armament components. The system further interacts with the operator by the inclusion of graphical user interfaces (GUI's), which are typically video display screens. The GUI's allow the operator to monitor system status and actuate desired system functions. All of the components are connected by a single common bus to a central bus controller. The central bus controller directs the flow of information along the bus between the central controller and the various components.
As armament control systems have evolved over time, the engineering processes used to develop these increasingly complex systems have undergone corresponding evolutions. Not long ago, engineers would brainstorm solutions to problems in their minds and transfer them to paper by hand. These drawings could then be used by fabricators to construct prototypes. The prototypes were then field tested to determine whether that particular design met the problem criteria. If the prototype did not acceptably solve the problem, modifications were made or new ideas were tried. This involved repeating the steps of brainstorming, drafting, fabrication, and testing. This “trial and error” process was iterative in nature and proved to be both lengthy and labor intensive.
The application of computers to the conventional design process has brought about several improvements. Computer drafting programs created a cost savings by streamlining the drawing step through minimizing the time it took a draftsperson to prepare drawings and modify the drawings in subsequent design process iterations. With the advent of Computer-Aided Engineering (CAE) tools, the design process could be further streamlined by minimizing the amount of iterations that needed to be performed before a satisfactory solution was obtained. CAE tools permit engineers to perform modeling and simulation of specific tasks performed by the system. Through modeling and simulation, many unacceptable solutions to the problem can be eliminated without the need to fabricate expensive prototypes or undertake lengthy and costly testing.
The resulting streamlined engineering process produces satisfactory results for a majority of engineering applications. However, this process cannot provide a smooth and efficient flow for the development of multi-component armament systems. In a multi-component armament system, there can be at least several different subsystems that are typically developed concurrently by different engineering teams. This type of parallel development, while compressing the time needed for the development cycle, creates communication difficulties between different development teams. The different subsystems ultimately must be combined with one another in the design process as part of an integration process step. During integration, the different subcomponents are combined as a complete multi-component armament unit that is then tested as a completed system. It is typical that the completed system must undergo a series of modifications in order to debug problems that arise during the integration testing process. The additional steps of integration and testing of the overall system, when individual subsystems have already been tested, adds length and cost to the development process.
The assignee of the present invention has developed a Simulation-Emulation-Stimulation (SES) process that streamlines the complex development process for integrated multi-component weaponry systems. The SES process addresses the communication issue by creating a virtual armament simulation system that each development team can use to simulate the characteristics of the complete system during the development of a particular subsystem, thereby minimizing or eliminating problems that may be encountered during integration and testing. The virtual armament simulation system includes a virtual prototype of each subsystem. The virtual prototypes simulate the characteristics of each subsystem. Each team can then develop their particular subsystem within the simulation of a real world installation. As with other types of existing control systems, components of the virtual armament SES system and the virtual prototypes are linked in communication by different communication channels, for example, a single MIL-STD 1553 bus or an Ethernet link. A more detailed description of the SES process is provided by, Huang, et al. in, “System Integration Laboratory—A New Approach to Software/Electronics System Integration” (1996). The paper describes a modeling and simulation based development and integration approach adopted for the Bradley Fighting Vehicle (BFV) M2A3 Engineering and Manufacturing Development (EMD) program at United Defense LP. The paper describes BFV A3 Upgrades, which were primarily in the area of fire control, electronics and software, and reports the development of a multi-purpose real-time simulation/emulation/stimulation (SES) and the system integration effort involved for the BFV A3 program. An SES was utilized to support system definition in the early stages and integration in later stages. A System Integration Laboratory (SIL) facilitated SES development. The SIL also provided the facilities and equipment for the overall system integration process.
During the system definition stage, the SES provided high fidelity modeling/simulation support to help define and characterize the system performance requirements, the system architecture, system sizing and timing, and interface implementation schemes between subsystems. During the integration phase the SES provided a lab integration environment with test sets, data reduction and acquisition capabilities, software upload/download and processor emulation facilities on tactical hardware; and stimulators to enable systematic testing and integration of subsystems. The SES, all target hardware and software units and subsystems, power supplies and ancillaries were accommodated in the System Integration Laboratory (SIL).
The integration tasks of the BFV A3 system involved the physical and functional connection of two electro-optical sights, an advanced fire control subsystem, a stabilized gun mount, a communications subsystem, an electronic warfare subsystem, power system, and other supporting subsystems. Most of the subsystems were equipped with processors and embedded software. The completed BFV A3 system was controlled by a turret processor unit. The system used point-to-point connections and a MIL-STD-1553 B databus to link all the subsystems to perform the combat mission. Like many major military electronic systems, the BFV A3 system had redundancy for the major components and the system was capable of performing in a degraded mode when it experiences non-fatal damage.
The paper describes computer simulation techniques in the context of computer-aided engineering (CAE) and comments on how the computer simulations can be run in real-time at a reasonable cost. One of the benefits of running simulations in real-time, according to the authors, is that it enables the interaction between simulation units to be in the form of live signals (i.e., with the same electrical characteristics as the end item). In other words, the simulations can emulate subsystems. This emulation capability expands the scope of simulation significantly. Further, with real-time simulation and emulation capability, engineers can construct stimulators to supply either the emulator or real systems with needed excitation that is similar to a field operation in a lab environment. These artificial excitations are indistinguishable from the real signals. This simulation, emulation, and stimulation (SES) provides a very powerful tool for the modern engineering process.
The paper goes on to describe the SES tool for the BFV A3 System integration tasks that was developed within the United Defense Systems Integration Laboratory (SIL). The SES development was started concurrently with system definition. Initially, the System Segment Specification was used to develop a relatively rudimentary but complete system simulation: the High Level System Simulation (HLSM), to understand the overall system characteristics early in the program and support system definition. As the design progressed, the simulation model was refined to reflect the new design. The HLSM evolved to the emulation model later to resolve issues on interfaces and communication. Eventually, a System. Integration Environment (SIE) was created. This SIE consisted of simulation models created by CAE tools, emulation software and hardware, and stimulators. The simulated counterparts of line replaceable units (LRUs) and subsystems, developed by third parties, were integrated into the SIE after initial laboratory acceptance tests, and tested extensively using this SIE to resolve performance and interface problems. Finally, the simulated counterpart was replaced by the actual LRU or subsystem in the reconfigured SIE to perform system level integration tests within the SIL.
Rapid prototyping methodology was used to create an overall system simulation before starting subsystem design. Conceptual emulation and stimulation were created using the same methodology. A rapid prototype provides an early working model of the system. This model provides an indication of system behavior and information essential for system definition. Alternative implementation schemes can be prototyped and performance characteristics obtained to support trade studies. Many technical issues associated with a complex system such as interfaces, throughput of processors, bandwidth of communication, interactions among subsystems, and soldier machine interfaces can be resolved through rapid prototyping.
In the BFV A3 Program, the MatrixX SystemBuild CAE tool (supplied by Integrated Systems Inc., (ISI)) was selected. Using this CAE tool, analysts and engineers can generate simulation models using building blocks supplied by the tool set. Simulation development consists of defining block diagrams of the system using rules defined by the tool. The tool then converts it into a simulation model, and hence the conventional equation generation and coding is streamlined into merely plotting the system block diagram. Tedious and time-consuming program debugging is replaced by accurately representing system behavior in the block diagrams.
The constructed simulation models were tested and analyzed in a powerful engineering workstation. The completed simulation models were then autocoded to generate the source code automatically. This automatically generated code was compiled and downloaded to a specific simulation controller. The simulation controller was a software and hardware system that allowed the source code of the simulation to run in real-time. A salient feature of the simulation controller was that specially constructed software/hardware interfaces could reside in the same chassis as the processor(s) to perform simulation. In the rapid prototype, the communication between the subsystems and components were looped through the special interface hardware/software. In this manner, the communications within the rapid prototype had the same functional and electronic characteristics as the completed system. The issues and problems associated with integration could be isolated and identified easily using this simulation controller. The solution candidates could be generated and tested within a fraction of the time required for conventional re-design, fabrication, and test.
The purpose of rapid prototyping was to construct an overall system model early in the program to assist system definition, assess many system issues and to better understand the integration problem. It was used to assist subsystem design and pave the way for successful system integration. During the program the constructed rapid prototypes (or SES) were constantly enhanced and refined to reflect the current design. The SES reflected the design in both function and structure. It allowed the models to be built separately. A special feature of the integration approach adopted, was the incremental integration environment. The constructed rapid prototype had many placeholders. Each line replaceable unit (LRU) or subsystem model occupied a unique placeholder within the SES. In the early stage of the program, the placeholders were filled by rudimentary simulation models of the LRUs and subsystems that could roughly simulate the functions of the BFV A3 system. This was used to formulate the system concept and assist the subsystem definition. As the design gradually progressed, those placeholders were replaced by more detailed and sophisticated LRU and subsystem models. Finally, when the actual LRUs and subsystems became available, the LRUs and subsystems replaced the simulation models one at a time, in the placeholder that resides in the overall integration environment. The corresponding placeholders allowed for appropriate software “plugs” to connect to the software/hardware interfaces, and through appropriate adapters, directly connected to the LRUs and subsystems due to early compliance to interface definition documents.
For the overall lab environment, there was almost no difference between this LRU or subsystem and the replaced simulation model. Using this approach, the tactical components (LRUs and subsystems) could be integrated one at a time into the overall system laboratory setup.
The first major program at United Defense that used a SIL was the Advanced Field Artillery System (AFAS) Advance Technology Demonstration Program. On this program, the new approach was used for a part of the system: the gun drives. On the AFAS ATD program the process was developed and perfected so that it could be used to develop the entire system for the BFV A3 program. During different phases of the program the configuration and functions of the SES equipment could evolve. In the long run, the easy reconfiguration and quick turn over of rapid prototyping can save substantial cost in system development due to the advantage of being able to identify potential problems and issues before commencement of design, and resolving them before detailed design, resulting in substantial overall savings compared with conventional approaches.
The significance of the BFV A3 System is that this was the first UDLP program that used rapid prototyping on a system that depended on a MIL-STD-1553 B databus for major communications. (emphasis not in original). The authors recognized that simulation can give rise to issues such as numerical region of stability and algebraic loops, to name a few. A second publication, Huang et al., “Modeling and Simulation (M&S) Based System Integration Approach”(1997), reports results of using the approach described in the previous paper through the delivery of the first prototype vehicle including, a seamless integration process, fault insertion capability, and software integration aid. This paper describes the use of M&S from early system development through test and evaluation and life cycle support. They also report on enhancements to the simulation (now called the Bradley Plus simulator or BPS) which will extend its usefulness. M&S was used from day one as a system engineering tool to validate the system specification. During design stage it was used as a design tool to aid the design process and tradeoffs. During system integration, M&S was used to accept and test the components and subsystems. The BFV A3 system engineering effort involved the definition and integration of many software and hardware subsystems, including two new electro-optical sights; new IFF (Identification Friend or Foe); an electronic warfare subsystem; new computers, fire control software and communications subsystems; and a new digital system architecture.
In order for M&S to be effective on the Bradley A3, it had to be ready on time to support the development process. To minimize the impact of the unpredictable and labor-intensive manually developed model software, off-the-shelf Computer Aided Engineering (CAE) tools were studied, analyzed, and selected. The CAE tools provided the modelers the capability to develop models rapidly and with relative ease. Labor intensive analysis, design and coding used in the development of conventional simulation models were discarded. Tedious and error-prone coding and debugging were replaced by automatic code generation and pictorial debugging tools.
Initially, the System Segment Specification was used to develop a relatively rudimentary but complete system simulation: the High Level System Simulation (HLSIM), to understand the overall system characteristics early in the program and support system definition. HLSIM included a program executive that controlled the system simulation, a set of place holders that contained the subsystems' and components' simulation models in the same configuration as the design, and a set of graphical user interfaces (GUI). The GUIs were constructed using the software tool sets and widgets. They gave near realistic views for visual understanding. The GUIs also served as user-friendly user input/output devices. As the design progressed, the simulation model was refined to reflect the new design. Special interfaces for software and hardware were constructed. The emulation model was produced using the infrastructure of HLSIM.
The interface signals originated from the same simulation models. The simulated signals were sent to specially built communication software blocks called user code blocks (UCBs). Outputs from the UCBs were used to drive interface hardware. The interface hardware was modified commercial off the shelf (COTS) circuit cards. These COTS cards, processor cards, wires, connectors, harness, and CAE tool generated simulation models comprised the overall M&S environment.
Using the easy to manipulate M&S environment, minimal effort was needed to build the communication UCBs. The communication protocols were identical to the tactical units and device drivers were equivalent commercial versions. Another salient feature of using this approach was that it allowed the real-time SES to take the advantage of any existing software/hardware prototypes or tactical units, that were available and at a later date, test sets. Whenever a subsystem or line replaceable unit (LRU) became available, the M&S environment would allow it to be plugged into the overall M&S environment to replace the corresponding simulation model. After the emulation was completed, it was also possible to generate all required external signals. Special build software models, in conjunction with specially configured software/hardware interfaces were able to generate near realistic excitation signals as input to the simulation/emulation models. Using this, the developers and users could operate the BFV A3 System and perform the functions in a near realistic “virtual environment” in the laboratory. This completed the overall SES Process.
The SES was used to emulate late delivered components and perform confidence tests for all delivered components. The SES and the M&S environment also provided the software integration process with powerful tools. The software bindings between Computer Software Configuration Items (CSCIs) were exercised on simulated CSCIs before the completion of tactical CSCI tests.
The core of the BFV A3 System is the MIL-STD-1553B high speed digital databus that links all electronic/software subsystems and LRUs. (emphasis supplied). Within the BFV A3 System, there is a bus controller (BC), a backup bus controller, and over 20 remote terminals (RTs). To test and evaluate the operation of the system requires the capability to inject faults into the system and be able to detect them. Within the M&S environment a databus fault injection feature was developed, tested, and used as both an integration and testing tool. This feature allows the direct control over words sent across the 1553 databus. This adds the capability to change data that the user does not normally have control over when the model is running; the capability to change messages quickly, on the spot, without a modification to the existing models; the capability to quickly test many scenarios; hastening debugging problems by not requiring the models to be changed and rebuilt to change messages; the capability of simulating the effects of actual failures; enhancement of the ability to integrate new hardware by allowing the operation to send messages to the hardware to determine the response; and checking possible changes to the interface with an LRU that may have been implemented with an old/newer ICD (Interfaces Control Documentation).
The SES methodology was used to implement this fault injection feature. A GUI was added to the existing control panels. This GUI had the capability of faulting multiple words simultaneously. Each of these faults could be enabled/disabled individually with the corresponding enable switch. The RX (receiving) and TX (transmitting) buttons determined whether the faulted word was the received or transmitted word of the LRU. The RT number, subaddresses, and word number were chosen using the given controls. Each bit in the word was then set with the buttons to x (no fault), 0 (bit is faulted to 0), or 1 (bit is faulted to 1). This GUI was connected to the Fault_Injection_Inputs UCB at the top level of the model. The Fault_Injection_Inputs UCB simply set global variables according to the faults input by the GUI. The code for the interface between the model and the bus driver was modified to examine these global variables for faults when the bus controller transmitted or received data. Each message in the model checked to see if a fault was intended for it. If so, this interface replaced correct data with faulted data before transmission, or in the case of a received word, replaced the correct data with faulted data after it is received, passing the faulted data to the model.
Modeling and simulation, with visualization and hardware-in-the-loop formed the backbone of the SES process. The early requirements could be tested in the M&S formed SES. The architecture and design information traveled back and forth to the simulated and emulated system. The M&S based system also controlled a turret test-stand and a Crew Station. Combined with vehicle dynamics model, structural model, vehicle mobility model, the lab Crew Station allowed a user to try out a vehicle in a virtual battlefield.
A very powerful feature of the SES was not used in the BFV A3 system. As a part of simulation development, functional equivalent units were developed for each Computer Software Configuration Item (CSCI) and used in overall SES demonstration. In several system demonstrations, partially developed tactical CSCIs were operated in conjunction with functional equivalent units seamlessly. In “Using Modeling and Simulation for Rapid Prototyping and System Integration” (1997), Huang et al. describe an SES (stimulation/emulation/stimulation) process developed as a rapid prototyping and system integration tool for the BFV A3 system. Using system specification as a guideline, a rough order of system requirements were generated and used to produce a simulation design documentation. Using the computer-aided engineering (CAE) tool, a high level simulation model was produced in a very short time duration. The architecture of the high level simulation model consists of three major parts, namely, the program executive (PE), the graphic user interface (GUIs), and the placeholders (PHs). The PE controls the timing, scheduling and other simulation related functions. The GUIs provide the engineers with convenient displays and controls. Each subsystem simulation model occupies a specific placeholder. The reason for using this approach is that the system model will experience many revisions and eventually evolve into a high fidelity system model. This process would go through many evolution stages to increase fidelity as design matured, and software and hardware for the simulation improved while keeping maximum re-usability of the developed software. Due to the complexity of the A3 system, a multi-processor based real-time environment was developed. This COTS system uses the commercial version processor cards and operating environment of the tactical units. In addition to producing similar functions as the A3 System, this unit also has to generate simulated environment and perform simulation control. Within this real-time environment, a simulation scheduler monitors each cycle of the simulation. This real-time environment uses parallel processing to achieve high throughput while maintaining affordable cost.
With the readily available interface hardware residing in the special real-time environment, the communication between those simulation models have the same characteristics as the target system (same electronical characteristics, communication protocols, and produced the same timeline, etc.). The emulation provides a powerful system tool for system tests and system integration. Since the system model architecture was based on placeholders for those subsystems, the interfaces were also ‘separated’ and ‘segmented,’ i.e., modulated. When a newer subsystem model became available, it could be put into a specific place holder to replace the corresponding older subsystem model. Similarly, the interfaces were gradually replaced by special produced hardware/software connection modules. To do this, instead of connecting the subsystems within the software model, each subsystem was connected to the specific hardware connection software module. The communication and interaction between the subsystems was looped through the interface modules and eventually via the hardware interface cards.
External stimulation such as the movement of the platform and other physical disturbance can be produced using a combination of simulation models and software/hardware interfaces directly interacting with the real-time environment. As required by testing engineers, SES was able to be modified as test and evaluation (T&E) tools. Significant T&E functions required the capability to inject faults into the system and be able to detect them. Using the rapid prototyping tool a databus fault injection feature was developed, tested and used as both an integration and testing too. This feature allowed direct control over words sent across the 1553 databus. This adds the capability to change data that the use does not normally have control over when the model is running, the capability to change messages quickly, or on the spot, without modification to the existing models, the capability to quickly test many scenarios, hastening debugging problems by not requiring the models to be changed and rebuilt to change messages, the capability of simulating the effects of actual failures, enhancement of the ability to integrate new hardware by allowing the operator to send messages to the hardware to determine the response and checking possible changes to the interface with an LRU that may have been implemented with an old/new interface control documents (ICDs).
The publication, Huang et al., “Simulation-Emulation-Stimulation A Complete System Engineering Process” (1998), describes the ongoing evolution of an integrated engineering methodology taking advantage of the advancement of computer technology by creating an System Integration Environment (SIE) that focuses on use of the Simulation-Emulation-Stimulation (SES) process. The original driving force behind development of this approach was the need to support the system integration of the Bradley Fighting Vehicle A3 System (BFV A3) (United Defense 1994f). A major concern for the BFV A3 System Integration EMD was that most of the subsystems would be completed and therefore supplied by subcontractors that were located in different and distant locations. Their subsystems would be delivered at different stages of the program. In order to ensure successful integration and demonstration of system performance, it was essential that subcontractors clearly understood how the system was partitioned, and the performance and interface requirements of the subsystems assigned to each subcontractor. Subcontractors were contractually required to deliver emulators/simulators of the subsystems to the prime to support the SES process. The system integrator was also responsible for generating alternative solutions, performing trade studies (United Defense 1994a) to select the best system architecture, and testing the architecture early, before design and building of the system. The tasks to verify system definition, monitor subsystem performance, document interface requirements in specifications and interface control documents (ICDs), and identify associated issues and concerns also belonged to the system integrator (United Defense 1994f, 1994b). This paper reports the evolution of this approach for producing rapid prototyping and performing system integration for the BFV A3 System and how it eventually evolved into a complete engineering process.
Just as real-time computer animation enables engineers to produce visual images that emulate objects in a “virtual environment,” the authors describe the emulation of communication signals, that is the generation of communication signals that have the same electronic characteristics and use the same hardware and software, as a real communication signal. Using a combination of computer models, communication software/hardware (device drivers, communication protocols, chip sets, etc.), the physical characteristics of the communication and process of the emulated system is duplicated.
Due to the complexity of the A3 System, a multi-processor based real-time environment was developed. This environment used commercial versions of the tactical units to produce a reconfigurable system integration environment. This SIE used the same processors, operating system, device drivers, communication protocols, and other software and hardware components as the tactical units to produce near realistic time line and responses with a fraction cost of the tactical units. During the development stage, this SIE also served as the real-time simulator first, real-time emulator and stimulator later. It filled the roles of all temporally missing (unavailable) pieces during development and integration duration. The modular construction of the system model facilitated hardware-in-the-loop simulation. After acceptance tests, delivered subsystems replaced the corresponding simulation model one at a time by using a hardware connector that was installed to this SIE. This delivered subsystem would operate with other simulated subsystems and perform system level functions.
The SIE used CAE tools to produce simulation models and functionally equivalent unit (FEU) software modules. These simulation modules and FEU software were used to emulate the function of a complete software of a system. An interesting feature is that these automatically coded software almost completely avoided coding error and code level debugging. The debugging process can be moved into a pictorial environment. A system block diagram was used to debug the design.
To support testing engineers, the SIE was enhanced to be used as a T&E tool. A significant T&E function required was the capability to inject faults into the system and be able to detect them. Using the rapid prototyping tool a databus fault injection feature was developed, tested and used as both an integration and testing tool. A fault injection GUI (graphic user interface) and software module was constructed and used to perform the fault injection. The test engineer used this GUI to perform either manual or automatic test functions. The complete test results that included event number, event, words, pass/no pass, and time stamp were automatically recorded in test reports using this SE. Engineers had been using this tool to analyze and test the communication system for the Bradley A3 for over a year according to the authors. A publication by Huang et al., “System Simulation Based Engineering Process” (1998), reports the evolution of an engineering process that has been used on several major projects/programs. The paper refers to the significant effort that has been applied in modeling and simulation (M&S) at United Defense. Real-time simulation has become relative common practice with the proliferation of high performance and relative affordable computation devices. Running simulation in real-time has many benefits: In addition to acquiring detailed performance related information, it also allows the interaction and communication between simulated components to use live signals (i.e., with the same electrical or physical characteristics as the completed system). For a system designed for human operation, real-time simulation would allow humans to operate the simulation through appropriate input/output devices and displays. In other words, using appropriate hardware interface components, engineers can emulate the operation of the system before building prototypes. This is called a virtual prototype (VP). Using the same technique, external excitations or stimulation can be produced to mimic the complete system operation in a controlled (lab) environment. Using this approach, a system integration environment (SIE) was created using commercially of the shelf (COTS) hardware and software. The plug-in-and-play technique allows, one at a time insertion of a delivered subsystem into the SIE through the interface hardware/software. The corresponding subsystem simulation models, will then be disconnected or removed from the system simulation setup. This approach enables complicated system integration tasks to be broken down into more manageable pieces. Early in the program involving the integration of Bradley Fighting Vehicle A3 System (BFV A3 System), a high level simulation (HLSIM) was developed to understand the developmental system and identify system issues and problems. The HSLIM was evolved into BFV A3 System Simulation (SSIM) and achieved real-time simulation capability to allow user juries to test the system before the completion of the design. The SSIM was evolved into the System Simulation/Emulation (SSEMUL) to test the communication (mainly the MIL-STD-1553B databus) and tactical software. Yet another paper by Huang et al., “System Design Using Virtual Prototyping Techniques” (1998), discloses a new approach for system design. The approach is based on a methodology that utilizes simulation, emulation, stimulation (SES) combined with computer aided design (CAD) to produce virtual prototypes (VPs). According to the authors, United Defense has developed an SES process as a standard system integration methodology. This approach requires a system integration team working closely with all Product Development Teams (PDTs) throughout the program. Each PDT is responsible for the development of an individual subsystem or component. From the early requirements, the system integration team creates a high level system simulation model (HLSM) to provide an early representation of the system and identify problems and issues. With a powerful computer, the HLSM can simulate real-time system operation and generate realistic time lines. The interfaces among subsystems are simulated first, and emulated later. The system emulation allows communication between two entities (models of subsystems or components) using the same communication protocols, signal levels, and will produce the same time lines as the final system. Using commercial off the shelf (COTS) HW/SW, the emulation can be achieved quickly and economically. Next, SES produces stimulation for the system. A combination of computer simulation models and COTS HW/SW produce needed stimulation to excite a simulation model or a “real” object for test and evaluation purposes. A simulation controller is produced using graphic user interface (GUI) tools. The GUI tool produced controller may have a combination of “virtual” hand controllers such as knobs, slides, switches, and joysticks. Computer displays provide excellent status feedback for testing simulation. High quality video images can produce near realistic views of the hand controllers. These virtual control knobs, slides, switches, etc., are operated in the same manner as the “real things” through input devices (computer keyboard, touch screen, mouse, or joystick). Behind the “virtual” hand controllers and displays, software sockets and other communication schemes connect the virtual controls directly to the corresponding computer models. Through these virtual input devices, operators can test human factor related issues in a lab environment. A control station mockup can be constructed using a combination of computers and COTS HW/SW. Users can evaluate a controller design before controller hardware is built by using this lab setup. An interesting feature of the lab setup is that environmental or other external excitation, such as electronic interference, sensor data, or physical disturbances can be introduced by using a combination of simulation models and COTS HW/SW. To add more “virtual reality,” computer images of complicated objects can be extracted directly from CAD drawings, and driven by powerful software on the computer monitors.
Similarly, video images can be connected directly to the real-time simulation to produce “virtual feedback” to the operator. Using ground database (information about terrain, soil property, etc.), computer programs can produce six-degrees of freedom (three linear and three rotary) movement disturbances and views to the “virtual driver.” The virtual driver can drive a simulated vehicle on a “virtual road.”
VP can supply the designers with complete system information in a lab environment before the start of detailed design. Many alternatives of design can be tested and evaluated with minimal cost and within a very short time frame. This virtual prototyping methodology is directly derived from the SES process. A collection of simulation models, high fidelity video images, and COTS HW/SW constitutes a system integration environment (SIE). This SIE provides the basis for a systematic approach to system integration. When a subsystem becomes available, through the reconfigurable software and hardware, it can be connected to the lab setup while the corresponding subsystem simulation model that resides in a particular placeholder is disconnected. The delivered subsystems are inserted into the lab setup one at a time. In this manner, the delivered subsystem will operate with simulated all other components.
This SES methodology has evolved smoothly into a virtual prototyping process. Almost all the software components developed in simulation, emulation, and stimulation became building blocks for the construction of VPs. The virtual prototyping effort is fully linked with all design efforts on the program. The structure of the VP also supported incremental system integration at a later phase of the program. Subsequently, the VP was used as a training device. T&E, and P3I functions could also be performed using the VP.
Presently, there exists a need for an armament control system design that can serve as the armament control system in the virtual environment of the development/simulation process, such as the SES process, and that can also serve as the actual control system for a multi-component armament system in the real installation. This control system should be dynamically reconfigurable to control a virtual prototype, a real component, or both. Additionally, there is a continuing need to provide a control system for a multi-component armament system that is scalable, easily upgraded, and that has improved usability, flexibility, and interoperability.